Means for throttling fluid-pressure-operated devices



June 5, 1928.

E. FALCKE MEANS FOR THROTTLING FLUID PRESSURE OPERATED DEVICES Filed May 1, 1924 m a m w Inventor": Emil FalcKe,

His Attorney Patented June 5, 1928.

- STATES EMIL rAnckE, cs-seem;

G s-massacresa sassin meme country, A

CORPORATION on NEW YORK.

litmus-non; THROIDTLING rLorn-rnnssunn-ornnn'rnn DEVICES;

Application filed: May 1, 1924, Serial No.

M. his. yen ion re e t -flu d. pressure operated devices ofthfe reciprocating type in which the v movement ,ot the piston is controlled by an exhaustv valve and the invention has for its-object the provisionnof vimproved means; for automat'cally throttling the exhaust fluid. from: such devices to vary the operating speed of the piston. .Wlfllemy invention is, capable of general application to reciprocating pressure operated devicesg it is of particular utility when applied 1 to the pneumatic operating. mechanism of a railway motor controller which is arranged to operate the controller through a sequence of definite steps to control one ,or more, drivingmotors... In order to operate "such a; motorcontroller satisfactorily so that each step is quickly and accuratelyeffected, it is desirable if not absolutely necessary that the pneumatic operating mechanism operate at a greater c speed through, the first part ofeach; successive step than at the end ofthe step. For this; purpose it. has been proposed to use anadditionalvalve in conjunction with the usual exhaust valve for controlling the pneumatic-operating mechanism of such controllers;- and to arrange the additional yfa'lve so that, it is automatically opened only the beginningofeach Switching step. Such an automatically Controlled auxiliary valye arrangement is described and broadly claimed in' Patent 1,382,872, issued June 28, 1921, to John F.- Tritle. j

ilhe pre ent invention provides a more simple anc lessexpensive automatic controlling means forpermitting a high speed of the, step by, step pneumatic operating mechanism-.at the start of each step and gradually checking thespeed of operation at the end ofthe step. Brieflysp'eaking, this is accomplished by providing an exhaust conduit through which the fluid is exhausted from the pneumatic operating mechanism and which is so. proportioned and designed that the initial throttling efiect on the eXhausti-ngfluid: is very slight, but gradually increase's to'cli ck the speed of the operating mechanism; In this way when the pneumatic II'IGCl'la'iIIiSDf llS connected to operate a railway motor controller, the quick vinitial movement of the pneumatiq operating niechainisim' at thestart of each stepenables the total tiinef nterval' required for changing the motor connections to be materially 710,320, an in Germany May 12, 1923.

reduced and also insures aquick break of the connections that avoids arcing or burning of the controller contacts. Furthermore,

operation at the slower speed near the end of each step effectively preyents aver-shooting. or movement ofthe controller past the desired controlling position, and thereby in.- surescgreater, accuracy in the control of the motor circuits. x v

. For caubetter understanding of my invention, reference, is had to the following description taken in. connection with the accompanying drawings in which-Fig. 1 is a partial, view insection ofafluid pressure operating mechanism embodying my invention, and Fig. 2 is an. enlarged sectional view of certain parts thereof. .Thenovel featureszwhich, I believe tobe characteristic of; my. inventionv are set :forth with; particularity in the appended: claims. Referring, to, Fig; 1. of the drawing, the invention zlS shown as :applied to. one end of. a well-known type of double acting pres sure operating .mechanism .which comprises the cylinder .10 withinwhich the piston 11 reciprocates to rotate the. shaft 12 by means of the rack. and pinion. gearing. shownl. In

the double-acting type of pneumatic mechanisnr. shown the: rack and pinion mechanism is held; stationary by'balancing the air pressure exerted on the right hand side of piston 11 against an vopposing substantially constant pressure whichis either applied. to the left hand. side of .pis'ton 11, or preferably to a second pistonconnected to the other end of the rack and. operating in cylinder 10, as shown in thepreviously mentioned Tritle Patent No. 1,382,872. Hence, when the pressure is exhausted from the right hand side of piston 11 the opposing pressure predominates and moves the piston to the right a distance determined bythe amount of fluid exhausted from the righthand side of piston 11. Thus, .by successively exhausting pressure. from the right hand side of the ,piston 11- the shaft 12 may bemoved to and stopped in each of a. series of definite positions. The shaft 12. may be connected to operate any desired apparatus (not shown) such-for example-as the operating cam shaft of a railway motor controllerwhiclr it is desired to more in a step by step; manner through a series of definite operating positions.

For controlling the movement of the piston 11, an electrically controlled valve 13 is provided for admitting operating fluid from the pressure line 14 through the chamber 15 into the right hand end of cylinder 10 and for exhausting the operating fluid from the cylinder 10 through the chamber 16 and the exhaust conduit 17 to atmosphere.

As shown more in detail in Fig. 2, the valve 13 is of the double acting type and is arranged to cooperate with the inlet port 18 and the exhaust port 19 formed in the valve casing 20 when raised or lowered through operation of the valve stem 21 in admitting and exhausting fluid pressure from the cyl1n der 10. It will be observed that the exhaust conduit 17 in the preferred form shown, comprises a pipe bent into a spiral or other similar space saving curved form and has one end connected to the chamber 16 and the other end open to atmospheric pressure. According to the present invention the relative length and cross-section of the exhaust pipe 17 are proportioned to effect a predetermined increase in throttling effect after the initial flow of exhaust fluid from cylinder 10. It will be evident that with a pipe of given area of cross section the length may be varied to produce the throttling effect desired. In order to protect theexhaust pipe 17 from harmful temperature influences it may be advantageous under some conditions to oncase the pipe within the protective insula-' tion covering 22. For example freezing of any moisture condensing upon the inner walls of the exhaust pipe 17 is effectively prevented. As the freezing of the moisture necessarily reduced the cross sectional area of the pipe, the protective insulating covering 22 serves to prevent variation in the throttling effect of the exhaust pipe due to this reduction in its cross sectional area.

As thus'constructed and arranged the op erat-ion of my invention is as follows:

With valve 13 in the position shown, the right hand end of cylinder 10 is in direct communication with the pressure line 14 and hence the operating fluid in the cylinder 10 is at a pressure substantially the same as that in the pressure line 141. Under these conditions the opposing pressures on the piston 11 are balanced and the shaft 12 is held. stationary. If the valve 13 is now operated from the position shown to that in which the inlet port 18 is closed, and the exhaust port 19 is opened, the fluid under pressure in the cylinder 10 is exhausted' to the atmos phere through the chamber 16 and the ex haust conduit 17. Since the exhaust conduit is filled with air at atmospheric pressure at the time the exhaust port is opened, the initial flow of fluid from the cylinder 10 occurs very rapidly until the normal pressure gradient determined by the cross sectional size as well as the length of exhaust pipe is established. During this intervalthe resulting movement of piston 11 to theright is' conduit 17 finally reaches a value which de-' pends upon the relative length and cross section of the pipe 17, as previously pointed out. Thus the escape of air from the cylinder 10 is checked more and more as after the initial rush into the exhaust pipe 17 occurs, and'the speed at which the piston 11 moves to the right is correspondingly decreased. After the piston 11 has moved the required distance to the right to. bring the shaft 12 into the desired operating position further movement may be arrested almost instantly by operating the double acting valve 13 to close the exhaust port 19 and openthe inlet port 18. In this way'the piston 11 and, consequently, the shaft 12, may be stopped accurately atthe desired operat ing position. 1

Further operation of the piston 11 and the shaft 12 to the-nextsucceeding operating position is accomplished by again operating the valve 13 to close the inlet port 18 and open the exhaust port 19. Due to the sudden pressure equalization in the exhaust conduit 17, the piston 11 initially moves quickly and the subsequent throttling eflect of the exhaust conduit again reduces the operating speed of the piston preparatory to reclosing the valve 13 to stop the piston accurately at the next succeeding position.

What I claim as new and desire to secure by Letters Patent of the United States is 1. In a fluid pressure operated device, the combination of a cylinder, a piston movable to an intermediate position therein, a valve for exhausting fluid from the said cylinder to control the movement of said piston to said position, and an exhaust conduit extending from said valve having. a relative length and cross section such as to effect a predetermined increase in the throttling effect on the fluid exhausted upon the opening of said valve and thereby automatically decrease the rate of movement of the piston after a rapid initial movement thereof.

2. In a fluid. pressure operated device, the combination of a cylinder, a piston movable therein, a valve for exhausting fluid from said cylinder to control the movement of said piston, and means comprising a pipe of relatively small cross section and substantial length for throttling "the fluid exhausted upon the opening of said valve and thereby automatically retarding the movement of said piston after a rapid initial movement thereof.

3. In a fluid pressure operated device, the combination of a cylinder, a piston movable upon the opening of said valx e to automati- I cally decrease the rate of movement of the piston after a rapid initial movement thereof, and a heat insulating covering for said pipe.

In witness whereof, I have hereunto set my hand this 12th day of April, 1924.

EMIL FALCKE. 

